Oven thermometer



1,635,652 H. WHITTIER OVEN THERMOMETER' July 12, 1927.

Filed Feb. 15, 1924 N704 M M f 1 w zaww Patented July 12, 1927.

v 1,635,652" P arsNTIoF'FIcE. 1

.HORACE R. WHITTIEB, or PLYMOUTH, connnc'rionr.

- OVEN ER OME'TER.

Application filed February. 15, 1924." Serial No. 693 101.

'This invention re'latesto those thcrmometer's which are more particularly designed to A "be fastened to the Side W rather than thefront walls ordoors, of insulated elec-' tricallyheated ovens, although, of'course,

e1; s andvapors c n escape In the accompanying drawings Fig. 1

5 shows-a side elevation ofa thermometer which embodies the invention applied to the insulated side wall of an oven. Fig. 2 shows a section on the plane indicated by the dotted line 22 on Fig. 1. Fig. 3' is a section o'nthe plane indicatedby-the dotted line 33 on Fig; 1. Figfii is aaview in elevation of the inner end of the device. The device has a cylindrical shell 1 of sufficient length to extend through the wall of the oven. This shell is preferably drawn toa cup's'hape from sheet metal so as to leave the inner end closed. Permanently at- -tach'ed to the open front end of: the shell is a face plate 2- This attachment-may be 0 accomplished by providing the front end of the shell with lugs 3and passing these logs. through correspondingly. shaped openings in; the'face plate and-heading them over onthe outside of the plate. The peripheral wall-at the inner end ofthe shell islthreaded and turning on this is a nut- 4. The shell passed from thefront through an opening which it closely fits until the face plate rests against the outside casing wall 5 of the oven. A clamping plate 6 is placed on the inner end of the shell against the inside sheathing wall 7 of the oven and then the nut is screwed on and turned up so as to tightly secure the parts in position and prevent leakage of gases and vapors through the oven wall about the shell.

Extending through the front plate and the rear closed end wall of the shell is a spindle 8. Fastened to the rear end of the spindle back of the closed inner end wall of the shell is an arm 9. A curved strip 10 of bimetallic thermo-responsive metal has one end pivotally mounted on a stud 11 pro ject ing from the closed inner wall of the nected with the arm attached to the spindle,

shell and. has its other end pivotally con-' so that'any change in shape of the ther mostaticstrip will throughthe arm impart arot-atlve movement to the spindle. A stop stud 12 is provided" for limiting the 0011* tracting 'nloveinent :of the thermostatic.

strip. Fastenedi by screwsltl tothe closed inner end of the shell in such :manner vasto protect thethermostatics strip is a guard cap.

14:. The endof' this capis provided with openings 15and its:edge=is located awayfrom and does not abut against the shelh-so that while it protects the strip from injury;

it does not'offer any material obstruction to the free circulation of heated an to and about the strip.

Attached to the-front end of the spindle .lS an arm 16.

This arm extends radially from the spindle in front of but close to the outerisurface of the face plate and its swinging end has an. angular-1y arrangedtell-tale plate or disk 17 which is desirably coated with white enamel and has a con trasting'in-dex linel8.

The face plate'which is segmental in out-' line has three outwardly projecting cars 19. The plate is attached to the shell so that the spindle. passes through, it near the axis of the segment and the telltale at the outer end of the arm on the spindle will travel on an are near the curved edge of the segment,

as the variations of temperature changes the positions of the parts. Fitted over the front of theface plate. and held thereto by engagement with the ears 19 is a casing 20.

"This casing isr of segmental shapefcorrespending .to the-sha pe of the face plate and it'encloses the pointer arm. edge of the casing is a thermometer-shaped slotv Qland the wall of the casing 'alongthe edges of this slot is provided with graduations and temperature indicating numerals.

ln'the device as made the casing is stamped from sheet metal and is coated on the'outside with white enamel, the graduations and numerals being shown thereon in black or colors contrasting with the white coating of the casing. which the device isapplied changes the indi As the temperature in the oven to eating or tell-tale 'disk on the end of the pointer arm is carried up and down closely adjacent to the slot in the curved edge of the casingand as the casing is white and the slot shows black the position of the white disk with its'indicating line is planly visible for a considerable distance away from the front of the oven. The deviceconstructed as In the curved i described may be attached to the side wall of an oven rather than the .front or to a swinging door so that it is out of the way and is not in position to be knocked and injured, and yet when attached to a side wall in this manner its indications are clearly seen. Substantially all of the parts of the structure are stampedor drawn to shape from sheet metal. N 0 glass is necessary to protect and close in the openings. The indicating arm is protected by the casing and there is no communication or passage be- "tween the openingin the casing and back of the closed end of the shell, except for the passage of the spindle which is fitted sufliciently tightto prevent the escape of vapors, gases and odors from the oven through the device. The device is so clamped in place that there is no chance for gases and vapors to work into the insulating material 22 betwcenthe outer casing and inner sheathing walls of the side wall. The action is very *ellicient for the thern1o-responsive strip,

while protected, is exposed to the full effect of the heated air in the oven.

The invention claimed is:---

l. An oven thermometer comprising a cydindrical shell having a closed inner end and the oveniwall, a spindle extending through the closed'end of the shell and the face plate, a thermo-responsive strip connected with the inner end ol' the spindle and adapted to turn itas thetelnperature changes, an arm fastenedto and extending radially from the tale plate, said casing having a curved edge wall with graduations thereon and a slot adiacent the inside of which the tell-tale plate is movable.

QmAn oven tliernion'ieter comprising a cylindricalshell having a closedinner end and adapted to fit an openin .in an oven wall, a face plate attached to t e outer endvof the 0 shell and adapted to lie against the outer surface o't' the oven wall, anut threaded upon the inner end of the shelland adapted to clamp the parts to the oven wall, a spindle extending through the closed end of the II shell and the faceplate, a thermo-responsive strip connected with the inner end of the spindle and adapted to turn itasthe temperature changes, a protecting. cap secured to the end of the shell over the ltl181'1110 strip, an f arui fastened to and extending radiallyfrom the outer end of the spindle, agtell-tale plate attached to and extending angularly from. the free end of the. arm, a casingattached to the face plate'and enclosing said arm and II tell-tale plate, said casing having a curved edge wall with graduations thereon and a slot adjacent theinside ot'vwhich the tell-tale plate is movable. e i y i 3. An oven thermometer comprising a cy lindrical shell having a closedinner end and adapted to fit an openingin an oven wall,.a. face plate.attachedtothe outer end of the shell and adapted to lie against the outer sur.- face of the oven wall, a clamping plate loose on the; inner end of the shell and, adapted to lie a ainst the inner surface. of the oven wall, a1 nut i threaded upon. the inner end of the shell and adapted -to clamp the parts to the oven wall, a spindle extending through the closed end of theshell and the face plate, a thermoaresponsive strip connected with the inncrendot' the spindle and adapted to turn it as thetemperature: changes, a protecting cap secured'to the end i of the shell overthe thcrn1ostrip,an arru fastened to and extending radially from the outer end of the spindle, a tell-taleplate at tachcd to and extending angularly from the, free end of the arm, a casing attached to the) face plate and enclosing said arnrandtell tale plate, said casingvhaving a curved edge. wall with graduations thereon and a slot adjacent the inside of which thetelletale plate. is movable. i i

.i roaaon n. wr-nfrrmn. I 

